Split Image Into Grid

This tool runs entirely in your browser. The selected image is read with the FileReader API, drawn onto a hidden HTML5 canvas, and cropped cell by cell using drawImage(sx, sy, sw, sh, 0, 0, sw, sh). No pixel data is sent over the network — not to this site, not to any third party. Close the tab and everything is discarded from memory.

For an N×M grid, piece width is floor(imageWidth / M) and piece height is floor(imageHeight / N). For each row r and column c, the source rectangle at (c·pieceW, r·pieceH) with size (pieceW, pieceH) is copied onto a fresh canvas and exported as a PNG with canvas.toBlob(). The last row and column absorb any remainder pixels so the whole image is covered.

No. The image never leaves your device. Everything — reading the file, drawing on canvas, generating the output PNGs, and building the ZIP — happens inside your browser tab. You can verify this by opening your browser's Network panel while splitting an image: no outbound uploads are made.

Any raster format the browser can decode as a bitmap: PNG, JPG / JPEG, WebP, GIF (first frame), and BMP. Output pieces are always saved as PNG to preserve quality and transparency. SVG and HEIC are not supported because browsers cannot always decode them consistently to canvas.

In practice, up to about 8000×8000 pixels works on desktop browsers with 8 GB of RAM or more. Mobile devices usually top out near 4000×4000 because of stricter canvas memory limits. If the browser tab stalls or a piece comes out blank, reduce the source image resolution before splitting or choose a smaller grid.

Common uses: Instagram multi-post grids (3×1, 3×3, 3×5), jigsaw-style puzzles for classroom activities, tile maps for games, printable poster tiles across A4 sheets, or splitting scanned pages into sections. Each piece downloads as piece_r1_c1.png, piece_r1_c2.png and so on, so the sort order matches the grid from top-left to bottom-right.

To keep the tool fully inline (no external libraries), the ZIP is built in STORE mode — files are concatenated without compression. PNGs are already compressed internally, so the ZIP size is close to what a compressed archive would give you. Any standard archive tool (Windows Explorer, macOS Archive Utility, 7-Zip, unzip) opens the result without issues.